Comprehensive Programs For HPV-Related Cancer Prevention
New infections are benign unless they persist.
The cumulative rate of anal HPV infection in women (WSW) is 70%-90%.
Both cervix to anus and anus to cervix with inoculation in the same women is common.
There is a very low risk of cervical cancer or cancer precursor lesions in women who are younger than 30 who are HPV-negative or clear of HPV.
Clearance of anal HPV is common. Few individuals show persistence of anal HPV infection unless they are HIV-infected.
HIV strongly influences the developmental of anal intraepithelial neoplasia (AIN). AIN is very much more frequent in an HIV positive individual.
HPV screening for anal-rectal cancers as well as oropharyngeal cancers amongst high-risk groups of both men and women need to be developed.
The lifetime probability of getting an HPV infection can is over 80% in certain populations, and one is not able to predict who will become a carrier or will be able to be clear of the
infection. Routine immunization programs for the entire population is the only way to effectively control the infection so that future generations will be free of HPV. Improved programs in order to increase the availability and to make the cost more manageable across populations in both developed and developing countries would be necessary to achieve this goal.
It is unknown for how long either site serves as a source of infection.
The prevalence rates for men are steady across all ages, would suggest that men do not develop protection against the infection. The prevalence rates for women decreases as they get older.
Factors that affect the rates of infection between heterosexual couples including intervals between testing points, the rates of concordance or discordance at baseline (the rate at which each partner does or does not have an HPV infection) and difficulty in establishing sexual infection versus contamination.
Most cervical cancers in the coming years will arise in non-vaccinated women or women who already carry other vaccine at the time that they had vaccination and for whom the vaccine was not as effective.
The natural history of PIN is not known. Men in whom PIN is diagnosed are usually treated.
The high risk of HPV 16 and 18 strains are the strains most frequently found in PIN. Natural History of HPV in Anal Genital Cancers
High-grade AIN is a precursor to invasive anal cancer.
Penile intraepithelial neoplasia (PIN) is regarded as a precancerous condition.
PIN is a condition where the delve in the top layer of the skin and penis look to be aggressive but in most cases when this is followed over time the lesion does not progress into an evasive cancer of the penis.
School-based programs have been demonstrated to be the most feasible way to reach adolescents in many countries. In addition, national immunization days and campaign style programs can be considered. The possibility of incorporating the HPV vaccine into childhood or Expanded Program on Immunization (EPI) programs may also be considered. The most effective way of reaching children below two years of age is by early immunization and this would guarantee a high rate of coverage.
Cervical HPV persistence is the known necessary event in the development of cervical cancer.
The prevalence of HPV in PIN ranges from 60%-100%.
The prevalence of PIN is far greater and much more common than invasive cancer of the penis.
The cost that Merck sells the vaccine to private practitioners in 2013 is $135.00/dose (check this number). This indicates the cost of the vaccine is over $400.00 before considering the cost of administering the vaccine. Developing countries have recently negotiated with GAVI in persuading the HPV vaccine companies to lower their cost in developing countries. The HPV vaccine companies have negotiated with developing countries and GAVI to introduce special programs to lower the cost of vaccines in their country.
1. Natural History of Penile and External Genital HPV
2. Penile Intraepithelial Neoplasia (PIN)
Women with precursors to cancer of the cervix, vulva and vagina have significantly higher rates of anal cancer.
Pediatricians, general practitioners, public health workers, and school officials will all play important roles in developing a comprehensive program for HPV-related cancer prevention.
Organized public health programs would be needed to reach the pre-adolescent, adolescent populations with the vaccine, to ensure long term follow-up to make sure that the program is effective and that the vaccine is safe.
